Glucanocellulosic ethanol: The undiscovered biofuel potential in energy crops and marine biomass

Converting biomass to biofuels is a key strategy in substituting fossil fuels to mitigate climate change. Conventional strategies to convert lignocellulosic biomass to ethanol address the fermentation of cellulose-derived glucose. Here we used super-resolution fluorescence microscopy to uncover the nanoscale structure of cell walls in the energy crops maize and Miscanthus where the typical polymer cellulose forms an unconventional layered architecture with the atypical (1, 3)-β-glucan polymer callose. This raised the question about an unused potential of (1, 3)-β-glucan in the fermentation of lignocellulosic biomass. Engineering biomass conversion for optimized (1, 3)-β-glucan utilization, we increased the ethanol yield from both energy crops. The generation of transgenic Miscanthus lines with an elevated (1, 3)-β-glucan content further increased ethanol yield providing a new strategy in energy crop breeding. Applying the (1, 3)-β-glucan-optimized conversion method on marine biomass from brown macroalgae with a naturally high (1, 3)-β-glucan content, we not only substantially increased ethanol yield but also demonstrated an effective co-fermentation of plant and marine biomass. This opens new perspectives in combining different kinds of feedstock for sustainable and efficient biofuel production, especially in coastal regions

A validated ultra-performance liquid chromatography with diode array detection coupled to electrospray ionization and triple quadrupole mass spectrometry method to simultaneously quantify taurine, homotaurine, hypotaurine and amino acids in macro- and microalgae

A fast and reliable method for the simultaneous quantification of Taurine, Homotaurine, Hypotaurine and 19 amino acids in algae samples by Ultra-performance liquid chromatography coupled with diode array and tandem mass spectrometry (UHPLC–DAD-MS/MS) was optimized and validated. Target compounds were chromatographically resolved in less than 15 min. (ESI)-MS/MS electrospray ionization and pure analytical standards were used to confirm the identity of all analytes, while quantitation was carried out with diode array detection. Validation parameters of the method were satisfactory: Resolution of peak pairs was always higher than 1.55; all analytical curves showed R2 > 0.99, with working ranges between 0.04 mg/g to 33.1 mg/g and 9.13 mg/g to 107 mg/g and the Lack-of-fit test was not significant. The intra and inter-day precision of the method (expressed as relative standard deviation) were lower than 6% and recovery values ranged between 95% and 105%. The method was demonstrated to be robust to small deliberate variations of seven variables such sample weight, volume of hydrolysis reagent, hydrolysis time and temperature, derivatization time, column temperature and flow rate. The mean expanded uncertainty for all the target compounds were 0.7 mg/g with a coverage factor of 2. Method Limits of detection and quantification varied from 0.005 * 10−3 mg/g to 0.11 * 10−3 mg/g and 0.01* 10−3 mg/g to 0.22 * 10-3 mg/g respectively, allowing the routine determination of these bioactive compounds in algae extracts. Therefore, the method was successfully applied for the quantitative determination of the 22 target compounds in five seaweed commercial samples. Relevant compounds were quantified for the first time in the five algae species, namely: i) Taurine in Gracilaria longissima and Chlorella spp., ii) Gamma-aminobutyric acid in G. longissima and L. japonica, iii) Hydroxyproline in G. longissima, Ulva lactuca, Porphyra spp., and L. japonica and iv) Homotaurine and Hypotaurine in the five species studied.info:eu-repo/semantics/acceptedVersio

Arsenic speciation in edible alga samples by microwave-assisted extraction and high performance liquid chromatography coupled to atomic fluorescence spectrometry

Twelve commercially available edible marine algae from France, Japan and Spain and the certified reference material (CRM) NIES No. 9 Sargassum fulvellum were analyzed for total arsenic and arsenic species. Total arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion and ranged from 23 to 126 μg g−1. Arsenic species in alga samples were extracted with deionized water by microwave-assisted extraction and showed extraction efficiencies from 49 to 98%, in terms of total arsenic. The presence of eleven arsenic species was studied by high performance liquid chromatography–ultraviolet photo-oxidation–hydride generation atomic–fluorescence spectrometry (HPLC–(UV)–HG–AFS) developed methods, using both anion and cation exchange chromatography. Glycerol and phosphate sugars were found in all alga samples analyzed, at concentrations between 0.11 and 22 μg g−1, whereas sulfonate and sulfate sugars were only detected in three of them (0.6-7.2 μg g−1). Regarding arsenic toxic species, low concentration levels of dimethylarsinic acid (DMA) (<0.9 μg g−1) and generally high arsenate (As(V)) concentrations (up to 77 μg g−1) were found in most of the algae studied. The results obtained are of interest to highlight the need to perform speciation analysis and to introduce appropriate legislation to limit toxic arsenic species content in these food products

Monoclonal antibodies directed to fucoidan preparations from brown algae

Cell walls of the brown algae contain a diverse range of polysaccharides with useful bioactivities. The precise structures of the sulfated fucan/fucoidan group of polysaccharides and their roles in generating cell wall architectures and cell properties are not known in detail. Four rat monoclonal antibodies, BAM1 to BAM4, directed to sulfated fucan preparations, have been generated and used to dissect the heterogeneity of brown algal cell wall polysaccharides. BAM1 and BAM4, respectively, bind to a non-sulfated epitope and a sulfated epitope present in the sulfated fucan preparations. BAM2 and BAM3 identified additional distinct epitopes present in the fucoidan preparations. All four epitopes, not yet fully characterised, occur widely within the major brown algal taxonomic groups and show divergent distribution patterns in tissues. The analysis of cell wall extractions and fluorescence imaging reveal differences in the occurrence of the BAM1 to BAM4 epitopes in various tissues of Fucus vesiculosus. In Ectocarpus subulatus, a species closely related to the brown algal model Ectocarpus siliculosus, the BAM4 sulfated epitope was modulated in relation to salinity levels. This new set of monoclonal antibodies will be useful for the dissection of the highly complex and yet poorly resolved sulfated polysaccharides in the brown algae in relation to their ecological and economic significance

An introduction to vegetable crop production and plant breeding in Brittany

National audienc

Le charme discret des macroalgues : de nombreux débouchés nouveaux ou potentiels

International audienc

Fractionation and analysis of fucans from brown algae

International audienc

In vitro fermentation by human faecal bacteria of total and purified dietary fibres from brown seaweeds

International audienc